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Monoclonal antibody reactivity as a virulence marker for Legionella pneumophila serogroup 1 strains
E Dournon1, W F Bibb, P Rajagopalan
1Institut National de la Santé et de la Recherche Médicale, Hôpital Claude Bernard, Université de Paris, France.
Abstract:
Using a panel of nine monoclonal antibodies, we subgrouped 85 environmental and 129 clinical Legionella pneumophila serogroup 1 isolates from Paris, France. Patients were unlikely to be epidemiologically linked either with each other or with the 44 sampled environmental sites (14 air conditioning systems and 30 buildings) that were selected at random in the Paris area. According to their monoclonal antibody patterns, isolates belonged to 14 subgroups. Monoclonal antibody 2 recognized 121 (93.8%) of 129 clinical isolates and 30 (35.3%) of 85 environmental isolates (P less than 10(-9)). Of the eight patients infected with L. pneumophila not recognized with monoclonal antibody 2, seven were immunocompromised; only 46.3% of the 121 patients infected with L. pneumophila reactive with monoclonal antibody 2 were immunocompromised (P = .02). We conclude that monoclonal antibody 2 can be used as a marker for the more virulent strains of L. pneumophila serogroup 1.
Insights
Monoclonal antibody 2 identifies more virulent Legionella pneumophila serogroup 1 strains. This marker was found in most clinical isolates but fewer environmental ones, suggesting it targets strains causing severe illness.
Area of Science:
- Microbiology
- Immunology
- Epidemiology
Background:
- Legionella pneumophila serogroup 1 is a significant cause of Legionnaires' disease.
- Environmental and clinical isolates require accurate differentiation for source tracking and virulence assessment.
Purpose of the Study:
- To subgroup Legionella pneumophila serogroup 1 isolates using monoclonal antibodies.
- To identify specific monoclonal antibodies that can serve as markers for virulent strains.
Main Methods:
- Subgrouping of 85 environmental and 129 clinical L. pneumophila serogroup 1 isolates from Paris using nine monoclonal antibodies.
- Analysis of monoclonal antibody reactivity patterns to differentiate isolates.
- Statistical comparison of antibody reactivity between clinical and environmental isolates and correlation with patient immune status.
Main Results:
- Isolates were classified into 14 subgroups based on monoclonal antibody patterns.
- Monoclonal antibody 2 recognized a significantly higher proportion of clinical isolates (93.8%) compared to environmental isolates (35.3%) (P < 10(-9)).
- Patients infected with L. pneumophila not recognized by monoclonal antibody 2 were more likely to be immunocompromised (7/8) compared to those infected with antibody 2-reactive strains (46.3%) (P = .02).
Conclusions:
- Monoclonal antibody 2 is a potential marker for identifying more virulent strains of L. pneumophila serogroup 1.
- The differential reactivity suggests monoclonal antibody 2-reactive strains are more associated with severe disease presentation.
- This finding aids in understanding Legionnaires' disease epidemiology and virulence factors.